DE 199 44 875 A1, for example, discloses a ball screw with a spindle and a nut surrounding the spindle. Balls arranged between the spindle and the nut are arranged in such a way that the balls can roll in a thread groove formed on the outer surface of the spindle and in a corresponding thread groove formed on the inner surface of the nut. Radial through-openings are also provided on the nuts. Deflecting pieces are fitted in those openings for the return of the balls respectively from a run-out end of a common turn of the thread grooves to a run-in end of this turn.
The nut is configured as a one-piece sleeve with a circular-cylindrical casing. Each fitted deflecting piece is arranged in the associated through-opening of the nut and completely within the outer casing. The through-openings are usually produced by machining. In this process, burr may be produced at the rim of the through-opening, which is not only obtrusive but also may impair the satisfactory function of the ball screw. In particular, where the rim of the through-opening goes over into the thread groove of the spindle nut, burr can lead to considerable problems. When the deflecting piece is fitted in the through-opening and the rolling ball rolls out of the thread groove of the spindle nut and into the deflecting channel of the deflecting piece, or is pressed in by following balls, the ball may cant at the burr and block the circulation of the balls.